source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/blkid/resolve.c@ 821

/*
 * resolve.c - resolve names and tags into specific devices
 *
 * Copyright (C) 2001, 2003 Theodore Ts'o.
 * Copyright (C) 2001 Andreas Dilger
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the
 * GNU Lesser General Public License.
 * %End-Header%
 */

#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include "blkidP.h"
#include "probe.h"

/*
 * Find a tagname (e.g. LABEL or UUID) on a specific device.
 */
char *blkid_get_tag_value(blkid_cache cache, const char *tagname,
              const char *devname)
{
    blkid_tag found;
    blkid_dev dev;
    blkid_cache c = cache;
    char *ret = NULL;

    DBG(DEBUG_RESOLVE, printf("looking for %s on %s\n", tagname, devname));

    if (!devname)
        return NULL;

    if (!cache) {
        if (blkid_get_cache(&c, NULL) < 0)
            return NULL;
    }

    if ((dev = blkid_get_dev(c, devname, BLKID_DEV_NORMAL)) &&
        (found = blkid_find_tag_dev(dev, tagname)))
        ret = blkid_strdup(found->bit_val);

    if (!cache)
        blkid_put_cache(c);

    return ret;
}

/*
 * Locate a device name from a token (NAME=value string), or (name, value)
 * pair.  In the case of a token, value is ignored.  If the "token" is not
 * of the form "NAME=value" and there is no value given, then it is assumed
 * to be the actual devname and a copy is returned.
 */
char *blkid_get_devname(blkid_cache cache, const char *token,
            const char *value)
{
    blkid_dev dev;
    blkid_cache c = cache;
    char *t = 0, *v = 0;
    char *ret = NULL;

    if (!token)
        return NULL;

    if (!cache) {
        if (blkid_get_cache(&c, NULL) < 0)
            return NULL;
    }

    DBG(DEBUG_RESOLVE,
        printf("looking for %s%s%s %s\n", token, value ? "=" : "",
           value ? value : "", cache ? "in cache" : "from disk"));

    if (!value) {
        if (!strchr(token, '='))
            return blkid_strdup(token);
        blkid_parse_tag_string(token, &t, &v);
        if (!t || !v)
            goto errout;
        token = t;
        value = v;
    }

    dev = blkid_find_dev_with_tag(c, token, value);
    if (!dev)
        goto errout;

    ret = blkid_strdup(blkid_dev_devname(dev));

errout:
    free(t);
    free(v);
    if (!cache) {
        blkid_put_cache(c);
    }
    return (ret);
}

#ifdef TEST_PROGRAM
int main(int argc, char **argv)
{
    char *value;
    blkid_cache cache;

    blkid_debug_mask = DEBUG_ALL;
    if (argc != 2 && argc != 3) {
        fprintf(stderr, "Usage:\t%s tagname=value\n"
            "\t%s tagname devname\n"
            "Find which device holds a given token or\n"
            "Find what the value of a tag is in a device\n",
            argv[0], argv[0]);
        exit(1);
    }
    if (blkid_get_cache(&cache, bb_dev_null) < 0) {
        fprintf(stderr, "Couldn't get blkid cache\n");
        exit(1);
    }

    if (argv[2]) {
        value = blkid_get_tag_value(cache, argv[1], argv[2]);
        printf("%s has tag %s=%s\n", argv[2], argv[1],
               value ? value : "<missing>");
    } else {
        value = blkid_get_devname(cache, argv[1], NULL);
        printf("%s has tag %s\n", value ? value : "<none>", argv[1]);
    }
    blkid_put_cache(cache);
    return value ? 0 : 1;
}
#endif